1. Field of the Invention
The present invention relates to digital video recorders. More particularly, the present invention relates to communicating program identifiers from a digital video recorder (DVR) to a set top box (STB) independent of when the STB demodulates the associated program data.
2. Description of the Prior Art
FIG. 1A shows a prior art digital video recorder or DVR 2 installed between a set top box or STB 4 (e.g., a tuner for digital cable) and a monitor 6. The STB 4 demodulates a selected channel from a program signal 5 and provides an audio and video (A/V) signal 7 to the DVR 2. The DVR 2 may record the A/V signal 7 for playback at a later time, or pass the A/V signal 7 through to the monitor 6 as A/V signal 9. The DVR 2 further comprises a modem for receiving Electronic Program Guide (EPG) data over a telephone line 8. The user operates a remote control 10 to direct the DVR 2 to display the EPG data on the monitor 6 in a DVR graphical user interface (GUI). The user can peruse the EPG data in the DVR GUI to select various programs to view and/or record.
The remote control 10 is also used to control the operation of the STB 4; that is, the remote control 10 of the DVR 2 is intended to replace the remote control of the STB 4. Commands are sent from the DVR 2 to the STB 4 over a control line 12. For example, if the user selects a new channel with the remote control 10, the DVR 2 commands the STB 4 to tune to the selected channel. In another example, if a program the user previously selected for recording begins to air, the DVR 2 directs the STB 4 to tune to the appropriate channel.
Multiple System Operators (MSOs), such as AT&T digital cable, as well as other broadband providers may not want the DVR 2 to commandeer the user interface. Broadband providers may want to retain their format for displaying the EPG data in order to minimize the burden on their viewers when a DVR is added to their system. Further, broadband providers derive revenue through advertising information displayed with the EPG data, and prior art DVR systems that replace the user interface may diminish the advertising revenue derived by the broadband provider.
There is, therefore, a need for a DVR compatible with existing STB hardware that can also accommodate the existing STB GUI.